MODEL RELEASED. Foetal monitoring during labour. View of a woman in early labour attached to a cardiotocography (CTG) machine that monitors her foetus' heartbeat. The foetus' heartbeat is picked up by an ultrasound scanner strapped to her abdomen and printed by the CTG machine at left. The machine also records uterine contractions. The foetus' heartbeats are closely monitored during childbirth in order to detect problems such as foetal distress, which occurs when the baby's oxygen supply is impaired. In this, the first stage of labour, the neck of the uterus (cervix) dilates to allow the baby out of the body.